I. Field of the Invention
This invention relates to bumper systems for vehicles and more particularly to a unique bumper bar and method for making the same for use in a bumper system including an exterior fascia having inclined sections, a bumper bar secured to extending frame sections of the vehicle, and plastic foam between the bumper bar and the fascia.
II. Description of the Prior Art
Modern automotive vehicles typically employ bumper systems which include a bumper bar secured to the frame of the vehicle at either the forward or rear end, so as to extend transversely to the center line of the vehicle. The outer face of the bar is covered with a plastic fascia that is designed based on primarily aesthetic and aerodynamic considerations. The fascia may have surfaces inclined relative to the vertical, typically sloping downward and forward. Some or all of the space between the facing surfaces of the bumper bar and fascia may be filled with material such as a foam that absorbs energy between the two.
The system is intended to absorb as much impact energy as possible in the shortest distance possible for purposes of keeping the package size of the bumper at a minimum. Additionally, the mass of the system should be minimized to minimize the energy required to drive the vehicle and thus the vehicle emissions.
In order to achieve these criteria, the distance between the opposed surfaces of the bumper bar and the fascia should be minimized. However, the goal of employing a bumper bar with a conventional boxlike configuration with opposed vertical sidewalls, one connected to the frame and the other to the fascia, and with fascias employing non-vertical surfaces, is difficult to attain. This compromises the design goal of maintaining the bumper bar edge as close as possible to the vehicle exterior surface in order to meet, distribute and dissipate the energy that is absorbed during the collision.